Jittery during XYZ moves...

[harryball]

I'm working on my long run bat house grooves routine mentioned elsewhere on the forum. I'm running a .015" deep groove along almost the full length of the table every 1/2". I've created a file and am working with it creating "hops" on the Z axis.

I'm having intermitent jitters while running the file only when XYZ are changing at the same time. It is not consistent nor does it occur in the same place every time. I know it's not my file as I've changed it from simple to complex to simple to many moves to few moves to large hops to small hops... it's always the same if XYZ are moving at the same time I'm at hazard of getting a hard jitter.

It's a little like when the bot looses communication with the PC. The position is not lost though, it is dead on for the entire cut... just with hard jitters randomly hitting when all 3 axis move. It's almost like ramping calculations are getting involved. It does ramp slightly as the Z hop approaches and leaves.

I've changed my run speeds ranging from a high of 12 ips XY 6 ips Z to a low of 6 ips XY .5 ips Z. I still get jitters (not as hard a low speeds) when XYZ are moving.

If I remove all the Z moves it'll run flat out at 12 ips and never have a problem.

I'm running version .27, the newest windows software.

Ideas?

Robert

[Brady Watson]

Robert,
Post or send me your C:\Program Files\ShopBot\ShopBot 3\problem.log

-Brady

[harryball]

I didn't get this sooner and have been running several projects all day. This is what's in there...

'ShopBot Configuration Version 3.4.27 --- 10-30-2006 18:52:14
' Copyright 1997-2006 ShopBot Tools, Inc. All Rights Reserved.
VK,
VD, 1, 3, 0, 0, 2, 1, 0, .05, 0, 1, 1, -2500, -7500, 8800, 4600
VU, 1273.2395, 1273.2395, 1273.2395, 1273.2395, .05, , , .25, 13.8889, 4, 4, 4, 4, 1
VA, 74.0371, 29.9999, .9998, .0000, .0000, 15.3310, -14.9367, .0000, .0000, .0000, .0000
SA
SO, 4,-1
VS, 1, .5, 1, 720, 8, 3, 3, 1440
VR, .4, .4, .4, .4, .4, .4, .4, .4, .4, .4, 100, .15, 65
SW, 2
VL, -.5, 96.5, -.5, 48.5, -2, 8.0, -3.0, 8.0, 0, -500, 500, 5
VP, 6, 96, 48, 6, 1, 1, 0, 1, 1, 0
VC, 1.25, , , 1.00, 0, 50, 1.00
VB, .1, 8, .4, .3, , 0,
VI, 4, 0, 0, 0, X, Y, Z, A, 4, B
VN, 1, 0, 0
FS, C:\Documents and Settings\Shopbot\My Documents\ShopBot Cut Files\plyo_boxes\cutfiles, *.sbp, c:\SbParts\Custom
UN, SbEdit.exe
SM

ShopBot Diagnostic Information Version : 3.4. 27
----------------------------------------------------------------------- 1
Windows OS = 2, 5.01 Resolution = 1400 X 1050
Total Memory = 267,870,208
Starting Memory = 144,535,552
Available Memory 96,247,808
maxFileLines = 1000000 maxStack = 75000( 50000)
586 184614918

Control Box Firmware Version = 130 SerNum. -SBXXXXXXXalpha-xxx2
Port Number - 4 Speed - 4: 460800
Starting Command Line -
Sound = 1 SCreenSaver = 0

Last Stack Size 0 1
Last Steps Transmitted 7828
Last Steps Confirmed 7828
Data Over-Runs 0
Fixed Over-Runs 0

'Recorded Commands ----------------------------
C2,
FP, rg_test_1.sbp, 1, 1, 1, 1, 0, -0.00, 0, 0, 1, 1
FP, rg_test_2.sbp, 1, 1, 1, 1, 0, -0.00, 0, 0, 1, 1
FP, rg_test_3.sbp, 1, 1, 1, 1, 0, -0.00, 0, 0, 1, 1
FP, rg_test_4.sbp, 1, 1, 1, 1, 0, -0.00, 0, 0, 1, 1
FP, rg_test_2.sbp, 1, 1, 1, 1, 0, -0.00, 0, 0, 1, 1
JH,
FP, rg_test_1.sbp, 1, 1, 1, 1, 0, -0.00, 0, 0, 1, 1
FP, rg_test_1.sbp, 1, 1, 1, 1, 0, -0.00, 0, 0, 1, 1
SK,
C2,
JH,
FP, BatHouse_Fronts_E_Fast_Groove_Drill_Full_Sheet.sbp , 1, 1, 1, 1, 0, -0.00, 0, 0, 1, 1
JH,
FP, BatHouse_Fronts_E_Fast_Groove_Drill_Full_Sheet.sbp , 1, 1, 1, 1, 0, -0.00, 0, 0, 1, 1
FP, BatHouse_Fronts_E_Fast_Groove_Drill_Full_Sheet.sbp , 1, 1, 1, 1, 0, -0.00, 0, 0, 1, 1
JH,
FP, BatHouse_Fronts_E_Fast_Groove_Drill_Full_Sheet.sbp , 1, 1, 1, 1, 0, -0.00, 0, 0, 1, 1
C4,
SK,
C2,

[Brady Watson]

Robby,
Change your VR to the following & see if it helps you:

3D Threshold: 150
Minimum distance to check: .08
Slow corner speed: 35

If you find that the tool is too slow going into/out of a corner, bump the SCS up a little. 65 is too fast for what you are doing. You shouldn't need to change the other parameters.

Let me know how that works.

Also, If you are doing a little 'bump' in Z to raise it up and bring it back down, increase the Z plunge speed to 4 or 5 when running all out @ 10-12 IPS. The XY is slowing down to wait for the Z to do it's thing. You may have to hand code the speed in before it does a straight plunge.

You may be hitting a communication bottleneck running @ 12 IPS and this may be the result of your computer not being able to get steps out fast enough. Keep in mind too that once in a while the tool with stop, slow or pause briefly as the control box's brain refills the command buffer.

-B

[harryball]

Brady,

I'll give the changes a try when I get back to running bat houses.

To clarify just for my knowledge, are the settings in my file the default?

Robert

[Brady Watson]

Yes.

-B

[rob_bell]

as my name is similar to Robert's so was my problem. Initially when routing a xyz wave pattern I was getting serious machine jerk. With Brady's VR suggestions it ran as smooth as butter.


3691

thanks.

[benchmark]

Hi Rob

That is a very interesting pattern, how did
you achieve it.

Many thanks

Paul

[rob_bell]

you can acheive this by making a 1" ballnose travel in a sinusoidal path (z-axis is the amplitude) back and forth where every other pass is offset by 1/2 of the period.

In truth I didn't use any math to do it. I simply drew some arcs in sketchup and exported them as a partfile using a ruby script I've written(not so simply).

I'd bet a programmatically inclined person could acheive the same thing using excel.

Here's another view.


3692

[harryball]

I ran today with the new VR settings, that seems to have done the trick. Thanks Brady. If it recurs I'll let everyone know.

Robert

[patricktoomey]

Rob, I don't know if you've checked out VCarve Pro - http://www.vectric.com/ but it has some really cool programatic textures with adjustments to get different patterns.

[rcann]

I need help. I have a similar problem. I have a stand alone unit window XP 256 RAM no other programs but wizard. I shut down all programs before running a job. I have changed, recreated files, because I was told I might have a file problem. I bought new cable because I was told it could be the cables. I up-dated software because I was told I needed to. I sent the board to shopbot it's okay. I have just stripped everything down and reset it. I ran a simple name plate 6" x 24" at 1.7 in cedar and within 20 minutes the router had lost it's registation and was jitter bugg'in across the table.
Someone please help. Another Robb

[john_david]

Robert,
What machine are you running, PRT or ALPHA??
And what is your step down and spindle speed for the 1.7" travel speed?
Just thought I would ask before someone else does LOL
Maybe I can help

JD

[mikejohn]

Further to Patricks post on the wave pattern, and to help you not having to re-invent the wheel
look at this (http://www.talkshopbot.com/forum/show.cgi?tpc=2&post=35506#POST35506) thread.

.............Mike